Alloys for use at high temperatures



3,310,399 ALLOYS FOR USE AT HIGH TEMPERATURES James French Baldwin, 78Forest Ave., Locust Valley, N.Y. 11560 No Drawing. Filed July 10, 1964,Ser. No. 381,932

9 Claims. (Cl. 75-171) The present invention relates to nickel basealloys which consist essentially of nickel with substantial proportionsof chromium, molybdenum, tantalum, cobalt, titanium and aluminum, whichare highly corrosion and erosion resistant at the temperaturesencountered in gas turbines and jet engines, in the range of 1700 F. to2200 F. and have relatively great tensile strength at operatingtemperatures, as well as the required degree of elongation and creep.

The higher the temperature at which a blade or vane in a gas turbineengine can be operated the higher the efficiency of the engine, and itis likewise obvious that the blades and vanes should have a relativelylong life at the temperature at which they are to be operated. Thealloys of the present inveniton are particularly suited to fulfillingall of the requirements of a blade or vane for gas turbine engines athigher than conventional temperatures and this is shown by the abilityof the blades and vanes formed from alloys of the present invention towithstand exceedingly high operating temperatures for short periods oftime, or to withstand higher than normal operating temperatures forextended periods of time, dependmg upon whether the engine is intendedfor military or commercial use.

Among the alloys of the prior art which are currently used are thosedisclosed in the United States Patents Nos. 2,948,606, 3,005,704 and3,061,426, as well as 3,026,198.

Patent No. 2,948,606 requires a relatively large amount of tungsten andis suitable for use only to a maximum temperature of 2000 F., andgenerally at a much lower temperature, such as 1800 F.

Patent No. 3,005,704 is differentiated from the alloys of the presentinvention in that it includes no cobalt content in its alloys, and iscapable of operating up to a maximum of about 1900 F.

Patent No. 3,026,198 discloses alloys which require from 20 to 35% oftungsten, and which difler in many other respects from the alloys of thepresent invention. Furthermore the alloys disclosed in this patentdo nothave the properties required for extended operation at temperatures inexcess of 2000 F.

Patent No. 3,061,426 discloses other alloys which have different ratiosof the titanium and aluminum content than the alloys of the presentinvention, and further require the use of substantial amounts ofvanadium which are detrimental in the alloys of the present invention.Additionally, the alloys of this patent require no tantalum content, andare adapted for use-only at temperatures of the order of 1700 F.Whereas, alloys according to this patent have a density of 0.308 poundper cubic inch, alloys of the present invention have a density as low as0.297 pound per cubic inch. Alloys of the present invention generallyhave an incipient melting point from 20 to 25 F above an alloy of thispatent, later referred to herein as alloy #100.

The alloys of the present invention are characterized by their abilityto operate at temperatures in the range of 1700 F. to 2200 F. forrelatively long and acceptable periods of time, with adequate strengthand other properties so that they may be used as the alloy to form theblades of an extremely efficient gas turbine engine.

The present invention has for its object the provision of novel andimproved high-temperature, corrosion and erosion resistant alloys whichare able to withstand prolonged operation at temperatures of about 2000F. and

A United States Patent 3,310,309 Patented Mar. 21, 1937 Ice higher, andwhich have relatively long life under operating conditions at thesetemperatures.

The present invention has for another object the provision of novel andimproved high-temperature alloys of the class described which arecapable of being cast with relatively consistent results, asdistinguished from many prior art alloys which give erratic results,depending upon minute variations in the many variables in the castingprocess.

The alloys of the present invention also have relatively high incipientmelting temperatures so that they may be heat-treated at higher thannormal temperatures and may be operated at temperatures above ordinaryoperating temperatures with no danger of the blades being weakened byincipient melting.

The alloys of the present invention show a remarkable combination ofstrength and ductility at high temperature levels, and are superior tomost of those of the prior-art, combining these properties With otherproperties to an unusually high degree. Additionally, these alloys ofthe present invention show an unusually high thermal shock resistancewhich is much better than that of other high strength alloys.

Further, alloys of the present invention are less susceptible to bowingwhen used as stator vanes in jet turbine engines than conventionalnickel and cobalt base alloys now used for that purpose.

Moreover, the alloys of the present invention do not develop a sigmaphase after exposure for long periods of time, such as 1000 to 4000hours at temperatures in the neighborhood of 1500 to 1650 F., as iscommon with other nickel base alloys of generally similar strength.

Additionally, alloys of this invention can be successfully extruded,upset and forged, while conventional nickel base alloys, such as areused for jet turbine blades and vanes, generally are not susceptible tosuch operations, and inthe few cases where such conventional alloys havebeen extruded, upset or forged, it has been accomplished with onlyextreme difiiculty.

T-he alloys of the present invention respond readily to heat treatmentand show solution temperatures as high as 2300" F., and their readyresponse to aging imparts great stability for long periods of use andrestores strength and ductility after exposure to temperature in theregion of 2000 R, such as are used in the coating of blades and vanes.

The alloys of this invention by weight consist essentially of from 5.0%to 12.0% chromium, about 3.0% to 8.0% molybdenum, 2.3% to 10.0%tantalum, 5.0% to 15.5% cobalt, O to 7.0% titanium, 0.0% to 8.0%aluminum, up to 0.25% carbon, up to .050% boron, with zirconium up to1.0%, balance essentially nickel in a quantity of at least 45%. In thesealloys, the combined content of the molybdenum and tantalum varies from5% to 14%, and the combined content of titanium and aluminum varies from5% to 8.8%. It is preferable to hold manganese and silicon to a maximumof 1.0%, iron to not more than 5.0%, with a low content of phosphorus ofabout 0.02% maximum and sulphur about 0.02% maximum. Deoxidizers, suchas calcium, magnesium and rare earths can be used in the usual smallquantities in the preparation of the alloys.

Within the broader composition ranges of the present invention, thereare narrower ranges which yield the preferred alloy compositions of thepresent invention, one group comprising higher ranges of chromiumcontent with a relatively high molybdenum content and a relatively lowcobalt content, while another group includes alloys having lower rangesof chromium content with lower ranges of molybdenum and higher ranges ofcobalt.

Of these two groups, the first is preferred including 3 from 7.5% to 12%by weight of chromium, from 3.0% to 8.0% of molybdenum, about 10% (5.0%to 10.5%) of cobalt, from 2.3% to 10.0% of tantalum, up to 2.5% oftitanium and (from 5.0% to 7.0% aluminum.

The second group includes alloys which include from 5 5% to 8% ofchromium, from 3% to 6% of molybdenum, from 4% to 8% of tantalum, from1% to 2.3% titanium and from 4.0% to 8.0% of aluminum, and from 10% to15.5% of cobalt, preferably from 13.0% to 15.5%.

Such alloys will have compositions within the following broad range andone or the other of the following narrower ranges.

Broadest Range Broad Range 1.0% max 1.0% max Vanadium. Tungsten.Phosphoro Sulfur Nickel. Balance Balance The balance of the alloys isessentially nickel, but may include trivial or trace amounts of variousimpurities such as the following elements in amounts of substantiallythe following weight percentages as maximum amounts Tungsten (maximum)for each of the several elements:

Percent by wt. Mo-l-Ta 9.7510.75 Cobalt 9.50-10.50 Titanium 0.80-1.20Aluminum 5.75-6.25 Ti -I-Al 6.55-7.45 Boron 0.01-0.02 Zirconium0.05-0110 Manganese, (maximum) 0.10 Iron, (maximum) 0.25 Sulfur,(maximum) 0.015 Silicon, (maximum) 0.40

Group A Group B 0.3% max. 0.3 max. 7.542% 58%. 36%. 4 7-12.2% 1015.5%:1-2.3% 1-24%. 5.4-s.s%. 0.05% max. 1.0% max. 2% max. 0%. 2.5% max. 0.02%max. 0.02% max. Balance.

Columbium, (maximum) 0.10 Phosphorus, (maximum) 0.20 Vanadium 0 0.10

Nickel, remainder.

Percent Manganese (P ly about 0.10%) Some of the alloys of the prior artmost commonly used Iron f abl about 0,30%) 2.0 in gas turbines havespecification analyses, as follows, here- S lfu referably out 0.015%)0.20 inafter referred to as alloys 100, 101 and 102.

Carbon Manganese 0.124117% i138??? Sulfur 0.015 max. S111con 1 00 max oh o um. a 0015 00 0 y enum g y g 3.50-5.50.

0 um ium plus Tantalum.-. Mplybdenum and Tantalum T1tanium 0'75-1' 5'Aluminum 550-0 0 Titanium and Aluminum. 6 25-7 '1I3ungsten" 11.5-13.5% I

0r0n 0.01-0.027 0.1-02'7 00005-0015. Z1rcon1um obs-0.09% 0.03-0.0%005-012. o 1.0% max 1.5% max 3.00 max. 1 1 0.10% max 0.50 max. 9.0-11.0%1.00max. 1.00 max.

Remainder- Remainder.

Silicon, maximum 0.40 columbium, maximum 0.20 Phosphorus, maximum 0.02Vanadium, trace only.

The more specific and preferred composition range for the alloys of mypresent invention are as follows:

Percent by wt.

Carbon 0.08-0.13

Chromium 7.50-8.50 Molybdenum 5.75-6.25 Tantalum 4.00-4.50

It may be noted that alloys and 102 are of the:

usual run of chromium, molybdenum, titanium, aluminum and cobalt, withalloy #101 substituting tungsten for- 75 alloys will be set forth below.

Example No. 1 No.2 No.3 N0. 4 No 5 Carbon 0. 09 0. 07 0. 0. 07 0. 06Chromium- 7. 8 7. 7 7. 9 7. 8 7. 7 5. 8 4.0 3. 95 5. 8 (i. 2 2. 3 7. 987. 5 6.2 4. 4 8.1 9.0 11.8 12.0 10. 6 10.1 9. 75 9. 9 9. 9 10.0 2. 31.1 1. 0 2.1 1.1 6.0 6. 2 5.9 5. 9 6. 3 8. 3 7. 3 6. 9 8. 0 7. 4 0. 0180. 012 0. 012 0. 024 0. 012 0. 06 0. 1 0.09 0.07 0.1 Nickel(cssentially) Balance Balance Balance Balance Balance The alloy ofExample No. 1 had the following mechanical properties:

Standard tensile strength test specimens at room temperature showed anultimate tensile strength of 137,000 p.s.i., with 6% elongation and 8.4%reduction in area; and a yield strength with 0.2% elongation of 121,000p.s.i.

At 1800 F. and a loading of 85,000 p.s.i., specimens ruptured after 26.2hours, showing an elongation of 2% after rupture and an area reductionof 6.0%. When tested at 1800 F. and a loading of 29,000 p.s.i., thespecimens ruptured after 23.0 hours, with 2.5% elongation after ru-ptureand 2.2% area reduction.

At 1900 F. with 18,000 p.s.i. loading the test bar ruptured after 32.1hours with 2.4% elongation and 2.0% reduction in area.

The alloy of Example No. 2 had the following mechanical properties:

At 1800" F. tensile strength specimens of the cast alloy 000 p.s.i.rupture occurred at 111.3 hours with 8.3% elongation and 4.9% reduction.When tested at 2000 F. and a loading of 18,000 p.s.i., the specimensruptured after 63.4 hours, with 3.0% elongation after rupture and 2.1%area reduction.

Another specimen of the alloy of Example No. 3 had the followingmechanical properties:

Standard tensile strength test specimens at room temperature showed anultimate tensile strength of 138,000 p.s.i., with 6.0% elongation and11.5% reduction in area and a yield strength with 0.2% elongation of114,- 250 p.s.i.

Similar test specimens cast from the same heat showed the followingproperties on rupture, the column head in-gs indicating temperature,continuously applied axial stress in pounds per square inch, hours arupture, percentage elongation and percentage reduction in area, hours,and percentage extension prior to rupture.

Temp, F.

Percent Percent percent R.A. Ext.

Hours Long time creep and rupture tests on test specimens from virginmelts having substantially the same analysis as Example 3 gave thefollowing results:

Temperature 1,500" F 1,500" F 1,500 F. 1,500 F. l,700 F 1,750 F 1,800 F,1,950" F.

1 qi 00,000 55, 000 50,000 40, 000 25, 000 21,000 15, 000 8.000 Priorextension (hIS,) 360- 9 1, 9 0 I 4, 7- 0 4, 532. 7+ 1, 413. 7 1, 066. 11, 930. O 1, 253. 8 Prior extension creep, percent.-- 1. 038 4. 4813.004 0. 415 6. 930 8.048 10.015 6.105 Final elongation, percent 5- 7 98. 4 10. 1 10. 7 9. 5 d ti in area, percent 8 6. 3 3. 5 3. 9 11.2 19. 0

I Stopped at 1%. of 1.0%. At 1900 F. and a loading of 18,000 p.s.i.,specimens ruptured after 63.4 hours, showing an elongation of 3.0% afterrupture and an area reduction of 2.1%.

The alloy of Example No. 3 had the following mechanical properties: 7

Standard tensile strength test specimens at room temperature showed atensile strength of 161,000 p.s.i. with 10.0% elongation and 11.0%reduction in area; and a yield strength with 0.2% elongation of 141,000p.s.i.

At 1400 F. a tensile strength specimen of the cast alloy maintainedunder continuously applied axial stress of 85,000 p.s.i. ruptured after367.4 hours, and exhibited an elongation after rupture of 4.7%, and anarea reduction of 4.7%. At 1600 F. and 55,000 p.s.i. the specimenruptured at 105.1 hours with 4.6% elongation and 4.1% reduction. At 1700F. with 40,000 p.s.i. loading, the specimen ruptured at 71.6 hours with5.3% elongation and 4.8% reduction. At 2000 F. with 10,-

The alloy of Example No. 4 had the following mechanical properties:

Standard tensile strength test specimens at room temperature showed anultimate tensile strength of 145,000 p.s.i., and a yield strength with0.2% elongation of 119,000 p.s.i. 7

At 1400" F. tensile strength specimens of the cast alloy maintainedunder continuously applied axial stress of 85,000 p.s.i. ruptured after166.9 hours, and exhibited an elongation after rupture of 3.0%, and anarea reduction of 5.0%. At 1800 F. and a loading of 29,000 p.s.i.,specimens ruptured after 32.0 hours, showing an elongation of 4.5% afterrupture and an area reduction of 3.1%. When tested at 1900 F. and aloading of 18,000 p.s.i., the specimens ruptured after 53.0 hours, with2.0% elongation after rupture and 8.0% area reduction.

The alloy of Example N0. had the following mechanical propenties:

Standard tensile strength test specimens at room ternperature showed atensile strength of 140,000 p.s.i., with 5.0% elongation and 8.0%reduction in area, and a yield strength with 0.2% elongation of 125,000p.s.i.

At 1800 F. and a loading of 29,000 p.s.i., specimens ruptured after 14.1hours, showing an elongation of 3.1% after rupture and an area reductionof 4.6%. When tested at 1900 F. and a loading of 18,000 p.s.i., thespecimens ruptured after 41.4 hours, with 4.0% elongation after ruptureand 4.7% area reduction.

WEIGHT PERCENT OF ALLOY CONSTITUEN'IS Example No.6 No.7 No.8 No.9 No.10

Carbon 0.09 0.1 0.1 0.1 0. 1 Chromium 8.0 8.0 8.1 8. 1 8.1 Molybdenum 5.8 5. 9 6. 1 6. 0 6. 2 Tantalum 4. 3 4. 2 4. 2 4. 2 4. 4 10.1 10.1 10.310.2 10.6 9.8 10.1 10.0 9. 9 11. 8 1.0 1.0 1.0 1.0 1.05 5.9 5. 9 6.0 6.0 6.2 6.9 6.9 7.0 7.0 7.25 0. 012 0. 013 0. 012 0. 012 0. 0.1 0. 08 0.012 0.08 0. 0. 2 0. 2 0.2 0.2 0.0 0.0 0. 0 0. 0 0. 1 0. 1 0. 1 0. 1

0. 005 0.006 0.008 0. 004 0.1 0.04 l Balance Balance Balance BalanceBalance The alloy of Example No. 6 had the following mechanicalproperties:

Standard tensile strength test specimens at room temperature showed atensile strength of 149,000 p.s.i., with an elongation of 9.0%, and ayield strength with 0.2% elongation of 121,000 p.s.i.

Carbon mens exhibited 4% room temperature ductility as compared with711% for unaged specimens from the same heat and cast. Examination ofthe strain-aged and as cast specimens showed no evidence of the sigmaphase in the strain aged specimens.

The alloy of Example No. 8 had the following mechanical properties:

Standard tensile strength test specimens at room temperature showed atensile strength of 143,000 p.s.i., with an elongation of 8%, and ayield strength with 0.2% elongation of 118,000 p.s.i.

At 1400 F. tensile strength specimens of the cast alloy maintained undercontinuously applied axial stress of 85,- 000 p.s.i. ruptured after134.7 hours, and exhibited an elongation after rupture of 3.7%. At 1800F. and a loading of 29,000 p.s.i., specimens ruptured after 49.3 hours,showing an elongation of 3.5% after rupture.

Other melts of alloys approximating the composition of Examples 6, 7 and8 had the following analyses (Weight percent of alloy constitutents):

Example Chromium Molybdenum Tantalum 0. 08 Balance Balance ZirconiumNickel (essentially) Trivial elements, as given for Examples 6, 7 and 8.

Tests on specimens of different melts of alloys having the analyses ofExamples A, B and C gave the following properties:

At 1400 F. tensile strength specimens of the cast Temp.,F. 2% Elonga-Ultimate Percent; Percent alloy maintained under continuously appliedaxial Stress 151011 (p.s.i.) Elong, Red. ofArea of 85,000 p.s.i.ruptured after 339.3 hours, and exhibited 9 an elongation after ruptureof 3.1%. At 1800" F. and gg 13483 2:; 312 a loading of 2,900 p.s.i.,specimens ruptured after 52.4 58,1388 3.188 hours, showing an elongatlonof 5.1% after rupturev 81900 141700 1 The alloy of Example No. 7 had thefollowing me- 8,500 14,100 17.9 13.7 chanical properties:

Melt Revert Virgin Duo Melt Revert Virgin Duo Melt Revert Duo DuoTe1np., F 1, 500 P.s.i 50,000 Hrs. prior ex 1, 866. 7 Prior Ext. Creep,percent.-. 1.896 Final hrs 1, 868. 0 Final Elong., percent. 2. 4 FinalR.A.. percent 6. 6 Ultimate Tensile. 155,000 Elongation, perce 8.0 0.2%iel 123,000 Rupture, 1,400 F 85,000 p s (hrs. 176.6 Percent Elong... 4.01,800 F., 29,000 p.s.i. (1115.). 44.0 Percent Elong 4.0

1 No Rupture.

Standard tensile strength test specimens at room temperature showed atensile strength of 142,000 p.s.i., with an elongation of 11.0%, and ayield strength with 0.2% elongation of 112,000 p.s.i.

At 1400 F. tensile strength specimens of the cast alloy maintained undercontinuously applied axial stress of 85,000 p.s.i. ruptured after 205.8hours, and exhibited an elongation after rupture of 5.0%. At 1800 F. anda loading of 29,000 p.s.i., specimens ruptured after 51.4 hours, showingan elongation of 6.0% after rupture.

After strain-aging specimens of this alloy at 1650 F.

The alloy of Example No. 9 had the following mechanical properties:

Standard tensile strength test specimens at room temperature showed atensile strength of 141,000 p.s.i., with 8.0% elongation, and a yieldstrength with 0.2% elongation of 119,000 p.s.i.

At 1400 F. tensile strength specimens of the cast alloy maintained undercontinuously applied axial stress of 85,000 p.s.i. ruptured after 140.3hours, and exhibited an elongation after rupture of 2.7%. At 1800 F. anda loading of 29,000 p.s.i., specimens ruptured after 42.2

and 15,000 p.s.i. for over 1000 hours, strain-aged specihours, showing3% elongation.

in area, and a yield strength with 0.2% elongation of 126,000 p.s.i.

At 1400 F. test specimen showed an ultimate strength of 135,000 p.s.i.rupture with 3.0% elongation and 5.0% reduction in area; and a yieldstrength of 121,000 p.s.i. at 2% elongation.

At 1400 F. tensile strength specimens of the cast alloy maintained undercontinuously applied axial stress of 85,000 p.s.i. ruptured after 87.7hours, and exhibited an elongation after rupture of 4.2%.

At 1800 F. and at a loading of 85,000 p.s.i., the specimen rupturedafter 87.7 hours, showing 4.2% elongation and a reduction in area of2.4%.

At 1900 F. and 18,000 p.s.i. rupture occurred at 33.3 hours with 6.2%elongation and 9.3% reduction in area.

Alloys similar to those of Examples 6 to 10 may be heat treated andforged to yield forgings which display greatly superior properties, ascompared with the alloys of the prior art.

Tests were carried out on specimens of various heats, all falling withinthe following ranges:

10 198,000 p.s.i. (ultimate strength with 23.0% elongation and 20.0%reduction in area).

Long time creep tests or specimens of alloys falling within the narrowranges just given above, gave the following data:

The coated specimens were subjected to the procedure set forth in UnitedStates Patent No. 3,102,044 using 2000 F. for 4 hours, followed byheating at 1600 F. for 50 hours, while the sixth specimen above wassubjected to the same temperatures but without any coating material.

In stress-rupture tests of heat-treated specimens of alloys within thisnarrow range, the following data were observed:

Heat treatment, Te1np., Stress, Rupture Percent Percent F., hours F.p.s.i. Time, hrs. Eloug. RA.

2,250", 4 hrs. air-coo1ed 2,000 4 hrs. air-cooled 1,500 24 hrs.air-oooled 1,460, 16 hrs. air-eooled 1,700 38,000 20. 5 3. 8 2. 3 Same1, 700 33, 000 47.8 6.0 5.0

2,250, 4 hrs. air-cooled 1,550", 24 hrs. air-cooled- 2,000 4 hrs.air-eooled 1,400 16 hrs. air-cooled- 1,700 38,000 14. 8 3. 1 3. 2 Same1, 700 33, 000 48. 1 3. 9 3.3

Percent by wt.

Carbon 0086-0095 Chromium 7.96-8.09 Molybdenum 5.95-6.07 Tantalum5.99-4.46 Cobalt 9.8810.92 Titanium 0.84-1.06 Aluminum 5.99-6.17 Boron0012-0015 Zirconium 0081-0089 Silicon 0.25 Iron 0.035

Nickel, balance.

Tensile strength tests at 1400 results:

129,000 p.s.i. for 0.2% elongation;

147,000 p.s.i. (ultimate strength with 4.7% elongation and 6.2%reduction in area).

elon gand F. gave the following At room temperature: 142,000 p.s.i. for0.2% elongation;

Other tests indicate that the alloy specimens are better on rupture lifeby 35 to than similar heat treated specimens of U-700, analysis givenbelow.

One of these alloys was used to form first stage cast turbine bladeswhich were un'coated and mounted in a gas turbine alternated with bladesformed from a standard alloy, U-700 coated with Jo-Coat a standard bladecoating. 8

The alloy compositions were:

50 Example 6A, percent U-700 (Specification),

percent Carbon t 0.095 0. 030. 10 Manganese. 0. O3 0. 15 Zirconium 0.0520. 015

Sulfuri.- 0.002 0.2O

Cobalt 10.92 17-20 Chromium. 7. 96 14-16 Titanium 0. 84 2. 75-3. 75Molybdenum 6. 00 4. 5-5. 5 Aluminum- 6. 15 3. 75-4. 25 Boron 0. 012 0.025-0. 035

Tantalurm- 4.46

Nickel Balance Balance In a standard, low-cycle, thermal fatigue test inthe first stage of a gas turbine of the airplane type, the blades wereoperated at a temperature somewhat in excess of 1800 R, for 1000 cycles,each cycle consisting of 2 minute-s of hot operation followed by 8minutes of cold operation.

At the conclusion of the 1000 cycle test, alloys substantially inaccordance with the analysis of Example 6A, showed the followingproperties:

Average blade extension 50% of the extension of similar blades of AlloyU-700.

Maximum blade extension was 40% of the maximum blade extension of bladesof Alloy U-700.

SM 302 10 times that of vanes of the alloy of Example 6A WI-52 timesthat of vanes of the alloy of Example 6A In another low cycle thermalfatigue test with a turbine inlet temperature of 1810 F. after 1440cycles, the bowing of vanes of the alloy of Example 6A was onlyone-fourth that of alloy WI- 52.

The alloy of Example No. 13 had the following mechanical properties:

Standard tensile strength test specimens at room temperature showed atensile strength of 138,000 p.s.i., with 7.0% elongation and an areareduction of 7.8%; and a yield strength with 0.2% elongation of 118,000p.s.i.

At 1400" E, tensile strength specimens showed an ultimate strength of131,000 p.s.i. with 4.0% elongation and 4.7% reduction in area and ayield strength with 0.2% elongation of 115,000 p.s.i.

At 1400 F. tensile strength specimens of the cast alloy maintained undercontinuously applied axial stress of 85,000 p.s.i. ruptured after 39.3hours, and exhibited an WEIGHT PERCENT OF ALLOY CONSTITUENTS ExampleNo.11 No. 12 1 No.13 No 14 No.15

Carbon 0.1 0. 1 0. 2 0. 1 0.13 Chromium. 8. 2 8. 2 8. 2 8. 2 8. 2 6.06.0 6.0 6.0 6.0 4. 2 4. 2 4. 2 4. 2 4. 0 10. 2 10. 2 10. 2 10. 2 10.010.0 10.0 10.0 10. 0 9. 9 1. 5 1.0 1.0 1.0 1.0 6.0 7.0 6.0 6.0 6.1 7. 58.0 7.0 7. 0 7.1 0. 012 0.012 0.012 0. 046 0.012 0. 08 0.08 0.08 0.080.1 2.1

Balance Balance Balance Balance Balance The alloy of Example No. 11 hadthe following mechanical properties:

Standard tensile strength test specimens at room temperature showed atensile strength of 157,000 p.s.i., with 10.0% elongation, and a yieldstrength with 0.2% elongation of 126,000 p.s.i.

At 1400 F. tensile strength test specimens showed an ultimate strengthof 126,000 p.s.i. an elongation of 5.0% and 7.8% reduction in area; anda yield strength at 0.2% elongation of 122,000 p.s.i.

At 1400 F. tensile strength specimens of the cast alloy maintained undercontinuously applied axial stress of 85,000 p.s.i. ruptured after 201.2hours, and exhibited an elongation after rupture of 5.1%, and areduction in area of 5.9%.

At 1800 F., and at a loading of 29,000 p.s.i., specimens ruptured after37.5 hours, showing 5.2% elongation, and an area reduction of 3.8%.

At 1900 F. and a loading of 18,000 p.s.i., specimens ruptured after 38.5hours with an elongation of 3.1% and an area reduction of 2.9%.

The alloy of Example No. 12 had the following mechanical properties:

Standard tensile strength test specimens at room temperature showed atensile strength of 139,000 p.s.i., with 5.0% elongation, and an areareduction of 8.2%; and

a yield strength with 0.2% elongation of 122,000 p.s.i.

At 1400 F, tensile strength specimens showed an ultimate strength of144,000 p.s.i., an elongation of 5.0% and a reduction in area of 7.8%;and a yield strength with 0.2% elongation of 122,000 p.s.i.

At 1400 F. tensile strength specimens of the cast alloy maintained undercontinuously applied axial stress of 85,000 p.s.i. ruptured after 105.0hours, and exhibited an elongation after rupture of 5.3% and an areareduction Of 5. 1%.

At 1800 -F., and at a loading of 29,000 p.s.i., specimens ruptured after32.4 hours, showing 4.0% elongation and an area reduction of 3.4%.

At 1900 F. and 18,000 p.s.i. rupture occurred after 29.0 hours with 3.8%elongation and 3.5% reduction in area.

elongation after rupture of 2.0%, and a reduction in area of 1.9%.

At 1800 F., and at a loading of 29,000 p.s.i., specimens ruptured after35.5 hours, showing 6.7% elongation, and an area reduction of 7.4%.

At 1900 F. and at a loading of 18,000 p.s.i. specimens ruptured after37.7 hours and showed 8.3% elongation and a reduction in area of 8.1%.

The alloy of Example No. 14 had the following mechanical properties:

Standard tensile strength test specimens at room temperature showed atensile strength of 136,000 p.s.i., with 7.0% elongation, an areareduction of 6.5%; and a yield strength with 0.2% elongation of 113,000p.s.i.

At 1400 F. tensile strength specimens showed an ultimate rupturestrength of 129,000 p.s.i. with 7% elongation and 6.5% reduction inarea; and with 0.2% yield strength at 114,000 p.s.i. I

At 1400 F. tensile strength specimens of the cast alloy maintained undercontinuously applied axial stress of 85,000 p.s.i. ruptured after 139.6hours, and exhibited an elongation after rupture of 2.3% with 3.5%reduction in area.

At 1800 F. and at a loading of 29,000 p.s.i., speci mens ruptured after38.5 hours, showing 9.6% elongation, and a reduction in area of 10.0%.

At 1900 F. at a loading of 18,000 p.s.i., specimens ruptured after 34.1hours, with an elongation of 7.6% and a reduction in area of 9.1%.

The alloy of Example No. 15 had the following mechanical properties:

Standard tensile strength test specimens at room temperature showed atensile strength of 148,000 p.s.i., with 6.0% elongation and 10.2%reduction in area; and a yield strength with 0.2% elongation of 122,000p.s.i.

At 1400 F. tensile strength specimens showed an ultimate rupturestrength of 133,000 p.s.i. with 2.0% elongation and 3.0% area reduction;and 0.2% yield strength of 125,000 p.s.i.

At 1400 F. tensile strength specimens of the cast alloy maintained undercontinuously applied axial stress of 85,000 p.s.i. ruptured after 113.1hours, and exhibited an 13 elongation after rupture of 5.9% and an areareduction of 4.7%

At 1800 F. and at a loading of 29,000 p.s.i. specimens ruptured after8.4 hours, showing 6.3% elongation, and an area reduction of 5.8%.

At 1900" F. and ate loading of 18,000 p.s.i. specimens ruptured after13.4 hours with 3.8% elongation and 2.7% reduction in area.

While the alloy of Example No. does not exhibit unusually good tensileand rupture properties at high temperature, it is an excellent alloywhich can be rolled, forged or extruded to form shielding and to providesheeting which have good corrosion and erosion properties at hightemperatures.

WEIGHT PERCENT OF ALLOY CONSTITUENTS 14 p.s.i., with 5.0% elongation and8.0% reduction in area at rupture and a yield strength with 0.2%elongation of 125,000 p.s.i.

At 1400 F. tensile strength specimens of the cast alloy maintained undercontinuously applied axial stress of 85,000 p.s.i. ruptured after 117.0hours, and exhibited an elongation after rupture of 4.4%, and an areareduction of 5.1%. At 1600 F. and a loading of 55,000 p.s.i., thespecimen ruptured after 78.0 hours, showing an elongation of 5.5% afterrupture and an area reduction of 5.4%.

At 1700 F. and a loading of 40,000 p.s.i., the specimen ruptured after67.4 hours with 6.8% elongation and 5.6% reduction in area.

When tested at 2000 F. and a loading of 10,000 p.s.i.,

Example No. 16 No. 17 No. 18 No. 19 N0.

Carbon .1 0.1 0.1 0.1 0.1 Chromiun1 8.0 8. 3 4. 5 5. 2 5. 5 4. 7 6.1 4.0 3.0 6.0 7. 3 3. 7 8.2 4.1 4.0 8.0 9. 8 12. 2 7.1 10. 0 10. 3 13. 5012.0 15. 4 13. 3

1.1 1.1 1.1 1. 5 1.15 6.0 5.95 0.0 7. 3 5. 3 7.1 7.05 7. 1 8. 8 6. 450.013 0.011 0.01 0. 02 0.01 0. 10 0.1 0.11 0.09 0.09 Nickel BalanceBalance Balance Balance Balance The alloy of Example No. 16 had thefollowing mechanical properties:

Standard tensile strength test specimens at room temperature showed atensile strength of 137,500 p.s.i., with 7.0% elongation and 10.0%reduction in area, and a yield strength with 0.2% elongation of 116,250p.s.i.

At 1400 F. tensile strength specimens showed an ultimate strength of143,000 p.s.i. with 116,250 p.s.i. elongation 6.0% and reductionin areaof 11.0%.

At 1400 F. tensile strength specimens of the cast alloy maintained undercontinuously applied axial stress of 94,000 p.s.i. ruptured after 108.7hours, and exhibited an elongation after rupture of 3.0%, and priorelongation of 2.005%. At 1800 F. and a loading of 29,000 p.s.i.,specimens ruptured after 75.1 hours, showing an elongation of 8.0%afterrupture. When tested at 1900 F. and a loading of 18,000 p.s.i., thespecimens ruptured after 107.3 hours, With 7.5% elongation afterrupture.

At 1400 F. and 85,000 p.s.i. the specimens ruptured at 340.5 hours withan elongation of 3.5% and prior extension of 2.42%.

Long time creep and rupture tests run on virgin-melt specimens of alloyof Example 16 gave the following data:

a specimen ruptured after 61.8 hours, with 20.7% elongation afterrupture and 17.8% area reduction.

Another specimen of substantially the same composition as the alloy ofExample No. 17 exhibited the following properties:

Standard tensile strength test specimens at 1400 F. temperature showed atensile strength of 141,000 p.s.i., with 5.0% elongation, 8.0% reductionvin area and a yield strength with 0.2% elongation of 119,000 p.s.i.

At 1400 F. tensile strength specimens of the cast alloy maintained undercontinuously applied axial stress of 85,000 psi ruptured after 171.5hours, and exhibited an elongation after rupture of 3.0%, and an areareduction of 3.1%. At 1800 F. and a loading of 29,000 p.s.i., specimensruptured after 52.7 hours, showing an elonga. tion of 5.0% after ruptureand an area reduction of 3. 9%. When tested at 1900 F. and a loading of18,000 p.s.i., the specimens ruptured after 61.0 hours, with 6.0%elongation after rupture and 6.3% reduction.

After being subjected to a creep test at 1400 F., with an axial stressof 85,000 p.s.i. for 326.4 hours, the specimen showed an elongation of5.4% and a reduction in area of 4.7% and failed at 328.0 hours.

Temp, F. 1,600 1,650 1,700 1,750 1,800 1,850

P.s.i 29, 000 29, 000 29, 000 29, 000 29, 000 29, 000 Prior Extensionhrs 2, 373. 6+ 1, 931. 2 645. 2 141. 1 75. 0 13.9 Prior Extension(creep), percent 0.992 8.846 6.198 4. 319 2. 977 Final hrs 1, 931. 4647. 0 143. 5 75. 0 15. 0 Final Elong., percent 10. 5 8. 0 6. 6 8. 0 8.4 Final R.A., percent 13.3 8. 6 8. 5 7.8

The alloy of Example No. 17 had the following mechanical properties:

Standard tensile strength test specimens at room tem- An alloy similarto the alloy of Example 17, after heat treatment for 4 hours at 2250 F.,followed by air cooling 4 hours at 2000 F., followed by air cooling,followed perature showed an ultimate tensile strength of 140,000 by 24hours at 1550 F. and air cooling, and finally by "1 heating at 1400 F.for 16 hours followed by air cooling, was the source of hot-forgedspecimens which gave the following data:

RUPTURE TESTS 1 3 perature showed a tensile strength of 145,000 p.s.i.,with 14.0% elongation and 13.7% reduction in area; and a yield strengthwith 0.2% elongation of 110,000 p.s.i.

At 1400" F., the specimen showed an ultimate tensile strength of 113,000p.s.i. and on rupture an elongation of Temp 0 Load, psi, Hours E1"percent 3.0%, an area reduction of 9.1%; and a yield strength at .2%elongation of 105,000 p.s.1.

28,000 600 4.3 At 1800" F. tensile strength specimens of the east alloy26,000 922.0 7.8 maintained under continuously applied axial stress of29,-

33 888 358 12 000 p.s.i. ruptured after 43.8 hours, and exhibited an18,000 154.0 7.2 elongation after rupture of 6.0%, and an area reduction16,000 97.0 9.2 of 110% o 54,000 14.7 2.3 At 1900 F. and a loading of18,000 p.S.l., specimens ig ggg :3 a ruptured after 68.3 hours, showingan elongation of 8.0%

56,000 200.0 15 after rupture and an area reduction of 13.0%.

Alloys corresponding to Example No. 20 with its high T cobalt contentrespond to extrusion and have been ex- 651 SLOPPQG- truded at a 16:1ratio, from a 5 ingot to a /2 bar.

WEIGHT PERCENT OF ALLOY ooNsTITUENTs Example N0. 21 No. 22 No. 23 No. 24No.25 No. 26 No. 27

Carbon 0.1 0. 08 0. 07 0.1 0. 09 0.12 0.10 Chromium 8. 2 8. 0 7. 8 7. 79. 7 8. 00 12. 00 Molybdenum" 0.0 8.0 as 4.0 3.0 4.00 a. 27 Tantalum 4.04.1 6. 2 7. 7 7. 2 8. 00 7. Mo plus Ta 10. 0 12.1 12. 0 11. 7 10.5Cobalt 10.0 10.1 9. 9 10.1 10. 2 14.00 10.15 T1tan1um. 1.0 0.9 0.8 1.21.1 1.0 1.04 Aluminum". 6. 0 5.8 5. 9 6. 0 6. 2 6. 0 0. 31 T1 plus Al.7. 0 6.7 6. 7 7. 2 7. 3 B 0ror1 0. 012 0. 024 0. 024 0. 014 0. 014 0.012 0. 011 Zireomum-.. 0.08 0.06 0.07 0.1 0.1 .09 0.09 N1ckel (essentBalance Balance Balance Balance Balance Balance Balance The alloy ofExample No. 18 had the following mechanical properties:

Standard tensile strength test specimens at room temperature showed atensile strength of 141,000 p.s.i., with a 5.0% elongation and 7.8%reduction in area; and a yield strength with 0.2% elongation of 130,000p.s.i.

At 1900 F. a tensile strength specimen of the cast alloy maintainedunder continuously applied axial stress of 29,000 p.s.i. ruptured after38.9 hours, and exhibited an elongation after rupture of 7.0%, and anarea reduction of 4.8%.

The alloy of Example No. 19 had the following mechanical properties:

Standard tensile strength test specimens at room temperature showed atensile strength of 125,000 p.s.i., with 13.0% elongation and 21.0%reduction in area; and a yield strength with 0.2% elongation of 95,000p.s.i.

At 1400 F., test specimens showed an ultimate tensile strength of129,000 p.s.i. with an elongation of 5.0% and a reduction in area of6.2%.

At 1800 F. tensile strength specimens of the cast alloy maintained undercontinuously applied axial stress of 29,- 000 p.s.i. ruptured after 37.4hours, and exhibited an elongation after rupture of 10.5%, and an areareduction of 4.8%.

At 1900 F. and a loading of 18,000 p.s.i., specimens ruptured after 36.3hours, showing an elongation of 7.0% after rupture and an area reductionof 6.0%.

The alloy of Example No. 20 had the following mechanical properties:

Standard tensile ,strength test specimens at room tem- Tensile data ofthe alloy of Example No. 21 follows:

Ultimate Reduction l 3111p, 0.2% Y eld, Tensile Elongation in area in Ip.s.i. Strength, in percent percent p.s.i.

Generally alloys that tend to show good strength at 1700 F. to 1800" F.fall oif markedly when reaching 1900 F. with a load of 20,000 p.s.i. ormore. The al- .loys of the present invention generally average 30 ormore hours at 1900 F. with 20,000 p.s.i. and with an elongation of 5.0%or better. Further, alloys such as the alloy of Example No. 21 have morethan a 200 hour life at 2000 F. 8,000 p.s.i., with 9.0% elongation andgreat strength between 1200 F. and 1700 F.

Test results on the alloy of Example No. 21 are shown in the followingtable:

Rupture Elongation Reduction Temperature, F. Load, Hours in percent inarea, p.s.i. percent I Stopped test at 1% extension.

The alloy of Example No. 21 is among the preferred vacuum melted alloysof this invention and standard test specimens show excellent oxidationand erosion resistance when subjected to a jet engine burner-can flameat rates 18 V Water for /2 minute, with a water flow at 250 pounds perhour, the test specimens being rotated at 1750 rpm. gave the followingcomparative data, expressed in hours before incipient crackingwasobserved:

higher than 0.6 Mach, at a temperature of 2100 F. for

200 hours in an 'uncoated condition. The following table compares suchdata with similar tests on specimens made of. alloy #1011 Grams Weightloss after 200 hrs. of Example No. 21 0.3 Weight loss after 200 hrs. ofAlloy #101 1.0

Similar tests on specimens coated with Jo-Coat (a standard gas turbineblade coating) but at 2100 F. gave the following comparative data:

Grams Weight loss after 200 hrs. of Example N0. 21 0.06 Weight lossafter 200 hrs. of Alloy #101 0.10

The following gives the results of tests of the static oxidation rate at2200 F. for 100 hours for the alloy of Example N0. 21 compared withalloys #100 and #101, on specimens machined to identical-length andshape:

' WEIGHT GAIN MGJCM.

Alloy 25m. 50 hrs 100 hrs.

Example No. 21, mg +7. 0 +10. 4 +20. 7 +255. 0 +313. 0 +591. 0 +28. 4'+50. 0 +117. 0

The .alloy of Example, No. 21 .of the presentinvention...

thus shows approximately one-sixth the oxidation at 2200 F. of alloy#101 and approximately one-thirtieth that of alloy #100.

Other testson the alloy of Example No. 21 gave the following data:

[0.6 Mach jet engine burner can flame erosion test at 2100 F.]

Sample Weight 100 hrs., 200 hrs.,

g. loss g. loss Comparative static oxidation tests of a test specimen ofthe presentinvention, compared with conventional alloys gave thefollowing results at 2200" F.

Static oxidation tests at 2,200 F. (Elms/cm. Total loss Alloy #101:

Original weight 3. 4830 After 24 hours 0310 After 148 hour 1064 Alloy#102:

Original weight 3.2516

After 24 hours 0086 After 148 hours 0340 Alloy #100:

Original weight 3. 1306 After 24 hours 0144 After 148 hours 0502 ExampleNo. 21:

Original weight 3. 3736 After 24 hours +.'0010 After 148 hours 0472 Thealloy of Example No. 22 had the following mechanical properties:

Standard tensile strength test specimens at room temperature showed atensile strength of 133,000 p.s.i., with 4.0% elongation and 7.6%reduction in area; and a yield strength with 0.2% elongation of 126,000p.s.i.

At 1900 F. tensile strength specimens of the cast alloy maintained undercontinuously applied axial stress of 18,000 p.s.i. ruptured after 35.4hours, and exhibited an elongation after rupture of 2.0%,and an areareduction of 2.0%

The alloy of Example No. 23 had the following me chanical properties:

Standard tensile strength test specimens at room temperature showed anultimate tensile strength of 144,000

p.s.i., with 4.0% elongation and 5.3% reduction in area, and a'yieldstrength with 0.2% elongation of 131,000 p.s.i.

' ""'At"1900 F. tensile strength specimens of the cast alloy maintainedunder continuously applied axial stress of 18,000 p.s.i. ruptured after30.4 hours, and exhibited an elongation after rupture of 4.0%, and anarea reduction After being subjected to a static oxidation test at 2000'F., a weight loss was observed of 0.0182 gram on the standard testspecimen. vA standard salt erosion test with jet fuel at 1900 F. and1000" rpm. conducted for 50 hours gave the following results comparedwith similar tests on alloys #101 and #102:

SALT TEST WITH J' ET FUEL-1900 F.-50 HOURS-1000 R.P.M

[1st 25 hours] Alloy of Example No. 23

Alloy #101 Alloy #102 Uncoated Uncoated Uncoated Coated Start grams 56.43 53. Q 58. 34 54. 22 25 hrs 56. 38 53. 90 57. 47 53. 93

Weight loss..... 0.05 0. 00 0. 87 0. 29

19 20 [2nd 25 hours] having a specific analysis as follows, gave thefollowing data:

55155233 11111: 22:32 23:33 211%? 23:33 018 Chrom1um 7.90 Weightloss..... 1.00 0.00 1.60 1.04 Molybdenum 403 TtlJtalvtzeighit Tantalum7.76 en Cobalt 9.90 of 1.05 0.00 2.47 1.33 Boron 0.012 Zirconium 0.10Titanium 1.13 Aluminum 5.90 The alloy of Exam le No. 24 had thefollowing meg ig zg iz gg 55 2; chanical properties Standard tensilestrength test specimens at room tem- ROOM TEMPERATURE TENSILE STRENGTHperature showed an ultimate tensile strength of 129,500 p.s.i. with 6.0%elongation and 11.0% reduction in area; Ultimate, 0.2% E o g Elongation,Red-in Area, and a yield strength with 0.2% elongation of 114,000 p.s.i.percent percent At 1400 F. the ultimate tensile strength was 140,000p.s.i. with 4.4% elongation and 7.0% reduction in area. 135'250 00o The0.2% elongation at 1400 F. was reached at 113,000 I p.s.i. RUPTURE TEsTsAt 1400 F. tensile strength specimens of the cast alloy maintained undercontinuously applied axial stress of Prior Percent Red. 111 85,000p.s.i. ruptured after 215.6 hours, and exhibited an Hm Elonggggelongation after rupture of 2.2%, and an area reduction of 1.51%. At1800 F. and a loading of 29,000 p.s.i., 1. M94300 4L2 401 1'9 Mspecimens ruptured after 58.6 hours, showing 6.5% elon- 1,800: F./29,000p.s. 45.8 7.6 10.1 gation. When tested at 1900 F. and a loading of18,000 1'900 p.s.i., the specimens ruptured after 78.0 hours, with 7.5%30 elongation after rupture.

A similar alloy to Example 24 from a diflerent heat and Test results onthe alloys of Examples Nos. 24 and 25 are shown in the following tables:

ROOM TEMPERATURE TENSILE STRENGTH TESTS Example .2% El0ng., Ult., p.s.i.Elongation, Reduetlon'in p.s.i. percent area (percent) 1400 F. TENSILESTRENGTH TESTS No. 24 117, 250 143, 500 5. 0 8.0 No. 25 117, 250 142,000 4. 0 8.0

RUPTURE TESTS Temp, P.s.l Hours Elongation, Reduction in area,

F. percent percent 1, 400 94,000 111.7 2. 5 Prior 1.09. 1,400 94,000113. e 3. 7 2.6 Prior 1.77. 1, 400 85,000 391. 3 3. 7 6. 0 Prior 2.04.1,400 85, 000 414.0 4.0 8. 0 Prior 2.26. 1, 800 29, 000 74. 6 8. 0 6. 51,800 29, 000 67.8 9. 5 9. 5 1, 900 18, 000 89.2 8. 0 8. 5 1, 900 00065. 2 6.0 8. 0

Total Hours Creep Temp., P.s.1 Hours Elongation, Prior to Extension F.percent Rupture Prior to Percent by wt. Cobalt 11.0 Boron 0.01 Zirconium0.048 Titanium 0.0 Aluminum 6.6 Iron 0.2 Manganese 0.2

Balance, substantially all nickel.

Specimens of this alloy showed the following physical properties:TENSILE STRENGTH Many of the alloys of the present invention aresusceptible to heat treatment, and may be extruded and hot forged.

Illustrative of the properties of heat treated hot forged alloyscorresponding to Example 3 are as follows:

(A) Heat treated for:

1 hour at 2290 F., then air cooled, 100 hours at 1550 F., then aircooled, 8 hours at 1900 F., then air cooled, 24 hours at 15 50 F., thenair cooled, 16 hours at 1400 F., then air cooled,

and hot forged, ruptured at 1400 F. under 85,000 p.s.i. stress at 181.1hours with 3.0% elongation and 5.7% reduction in area.

(B) Heat treated at 2290 F. for 1 hour, air cooled, 2000 F., 8 hours,air cooled, 24 hours at 1550 F., air cooled and 16 hours at 1400 F.followed by air cooling and hot forging ruptured at 193.3 hours with85,000 p.s.i. stress at 1400 F. with 3.0% elongation and 2.7% reductionin area.

(C) Heat treated at 2250 F. for 1 hour, air cooled, 8 hours at 2000 F.,air cooled, 16 hours at 1400 F. air cooled and 24 hours at 1650 F.followed by air cooling and hot forging, ruptured after 187.3 hoursunder 85,000 p.s.i. at 1400 F.

Forged, heat treated specimens of an alloy corresponding to Example 21showed the following results on rupture tests:

HEAT TREATMENT F. P.s.l. Hours Percent Percent El. R.A.

Specimens of a forged heat treated alloy corresponding to Example 25,showed the following results on rupture tests:

HEAT TREATMENT In general, the alloys of the present invention may beextruded from a 5" or 6" ingot to as small as 1.1 and 6" ingots havebeen extruded and then rolled to form a bar as long as 40 feet.

In general, the alloys of the present invention are exceptionally Wellsuited for use in the manufacture of blades for gas turbines and in suchuse are comparable in strength at 1800 to 1900" F. with blades made fromalloy #101, are better than blades made from alloy and much better thanblades made from al-loy #102 The alloys of the present invention ingeneral exhibit better static oxidation resistance than alloys #100,#101 and #102, and show no grain boundary attack at temperatures inexcess of 2000 F. The present alloys produce excellent cast structuresof great uniformity, which can be fully solutioned at about 2250 F. andcan therefore be stabilized and aged for greater strength and ductilityand are comparable with certain alloys containing 18% or more of cobalt,while having better overall properties including excellent oxidation anderosion properties.

The invention in its broader aspects is not limited to the specificsteps, process and compositions shown and described but departures maybe made therefrom within the scope of the accompanying claims withoutdeparting from the principles of the invention and without sacrificingits chief advantages.

What is claimed is:

1. A corrosion resistant nickel-base alloy for use at relatively hightemperatures consisting essentially of the following elements in theweight percent ranges set forth:

Percent Chromium 5-12 Molybdenum 3-8 Tantalum 2.3-10 Cobalt 5-15.5Titanium 0-7 Aluminum 0-8 Carbon 0-0.25 Boron 0-0.05 Zirconium 0-1.0

the balance of the alloy being essentially nickel, the total of themolybdenum and tantalum being from 5% to 14% and the total of thealuminum and titanium being from 5% to 8.8%.

2. A corrosion resistant nickel-base alloy for use at relatively hightemperatures consisting essentially of the following elements in theweight percent ranges set forth:

Percent Chromium 5-12 Molybdenum 3-8 Tantalum 2.3-10 Cobalt 5-15.5Titanium 0-2.5 Aluminum 4-8 Carbon 0-0.25 Boron 0-0.05 Zirconium 0-1.0

the balance of the alloy being essentially nickel, the total of themolybdenum and tantalum being from 5% to 14% and the total of thealuminum and titanium being from 5% to 8.8%.

3. A corrosion resistant nickel-base alloy for use at relatively hightemperatures consisting essentially of the following elements in theWeight percent ranges set forth:

Percent Chromium 7.5-12 Molybdenum 3-8 Tantalum 2.3-10

Cobalt 5-10.5 Titanium 0-2.5 Aluminum 5-7 Percent Carbon -0.25 Boron0-0.05 Zirconium 0-1.0

the balance of the alloy being essentially nickel, the total of themolybdenum and tantalum being from 7% to 13% and the total of thealuminum and titanium being from 5.5% to 8%. a

4. A corrosion resistant nickel-base alloy for use at relatively hightemperatures consisting essentially of the following elements in theweight percent ranges set forth:

Percent Chromium -8 Molybdenum 3-6 Tantalum 4-8 Cobalt -15.5 Titanium 1.0-2. 3 Aluminum 4.4-8 Carbon 0-0.25 Boron 0-0.05 Zirconium 0-1.0

the balance of the alloy being essentially nickel, the total of themolybdenum and tantalum being from 7% to 12.2% and the total of thealuminum and titanium being from 5.4% to 8.8%.

5. A corrosion resistant nickel-base alloy for use at relatively hightemperatures consisting essentially of the following elements in theweight percent ranges set forth:

the balance of the alloy being essentially nickel, the total of themolybdenum and tantalum being from 9.75% to 11.25% and the total of thealuminum and titanium being 6.55% to 7.45%.

6. A corrosion resistant nickel-base alloy for use at relatively hightemperatures consisting essentially of the following elements in theweight percentages set forth:

Percent Chromium 8.2 Molybdenum 6.0 Tantalum 4.0 Cobalt 10.0 Titanium I1.0 Aluminum 6.0 Carbon 0.1 Boron 0.012 Zirconium 0.08

and the balance of the alloy being essentially nickel.

7. A corrosion resistant nickel-base alloy for use at relatively hightemperatures consisting essentially of the following elements in theweight percentages set forth:

Percent Chromium 8.0 Molybdenum 4.0 Tantalum 8.0 Cobalt 14.0 Titanium1.0 Aluminum 6.0 Carbon 0.1 Boron 0.012 Zirconium 0.09

and the balance of the allow being essentially nickel.

8. A corrosion resistant nickel-base alloy for use at relatively hightemperatures consisting essentially of the following elements in theweight percentages set forth:

Percent Chromium 8.0 Molybdenum 8.0 Tantalum 4.1 Cobalt 10.1 Titanium1.0 Aluminum 5.8 Carbon 0.08 Boron 0.024 Zirconium 0.06

and the balance of the alloy being essentially nickel.

9. A corrosion resistant nickel-base alloy for use at relatively hightemperatures consisting essentially of the following elements in theweight percentages set forth:

Percent Chromium 7.9 Molybdenum 3 .95 Tantalum 7.5 Cobalt 9.9 Titanium1.0 .Aluminum 5.9 Carbon 0.1 Boron 0.012 Zirconium 0.09

and the balance of the alloy being essentially nickel.

References Cited by the Examiner UNITED STATES PATENTS 2,920,956 1/ 1960Nisbet et a1. -171 3,085,005 4/ 1963 Michael et a1. 75171 3,107,16710/1963 Abkowitz et a1 75-171 3,202,552 8/ 1965 Thexton 75-171 DAVID L.RECK, Primary Examiner. IHY LAND BIZOT, Examiner.

.R. O. DEAN, Assistant Examiner.

1. A CORROSION RESISTANT NICKEL-BASE ALLOY FOR USE AT RELATIVELY HIGH TEMPERATURES CONSISTING ESSENTIALLY OF THE FOLLOWING ELEMENTS IN THE WEIGHT PERCENT RANGES SET FORTH: 